220 МВ. W. ARCHER ON THE MINUTE STRUCTURE AND 
portion of the septum cutting off the first joint of the upper branch from the rami- 
fication-cell of the first degree (3”); 4th. The (whole of the) septum cutting off the first 
joint of the lower branch from the ramification-cell of the second degree itself (47); 
and, 5th, a very short side joining the two latter together, produced by the turning aside 
of the outgrowing extension of the ramification-cell of the second degree in its less 
advanced stage (5”). 
Leaving this lower minor or secondary branch (as in the case of the older and upper 
one) for the present, we come to a point whence it is far more difficult to follow out 
the structure. | 
On taking up the description of Ballia callitricha (Ag.), Harvey, as given by Agardh 
under the name Sphacelaria callitricha, the plant he had in view is thus, in part, de- 
scribed: ** Саше filis confervoideis vestito" *.... So also Prof. Harvey refers to the 
external ** plexus of filaments." : 
On looking at a piece of our plant, these “Ша confervoidea," or filaments, are indeed 
a prominent, but a very confusing feature, clothing, as they do, with a dense and 
intricately matted and tangled jungle the whole of the principal stems and some of the 
secondary rachises, the free ends of the filaments sticking about in every direction. 
This clothing might call to mind a tree densely covered with ivy, or, perhaps more fitly, 
might suggest a moss coated with Chroolepus aureum, only that the latter plant, when 
investing the moss, makes a smooth pile. 
The authors referred to seem not to have investigated the relations of this plexus 
of “confervoid filaments" to the more handsome distichously branched Badlia-plant. 
I therefore desired the more to try to **make head or tail" of the confusing object 
before me, so far as regards the accessory clothing of what might be regarded as the 
Ballia proper (Pl. XXVIII. figs. 1, 4, 15; Pl. XXIX. fig. 14). 
Not to speak of the general appearance and the similar thick-walled character of the | 
cells of these filaments, two characters would set aside any possible supposition that 
these were not really part and parcel of the make-up of the Ballia. One of these was 
the presence in every one of the here directly transverse septa, separating their compara- 
tively short quadrate joints, of a minute pair of pits with their stoppers (Pl. XXVIII. 
figs. 6, 7); the other, that when they branched it was seemingly by the interposition of 
a ramification-cell, but not of the same figure as those of the distichous stems and 
branches as described (figs. 6, 7). 
Looking more closely into the build-up of this clothing of the stems and some of the 
rachises of the plants, it is readily enough seen that this is most dense at the lower por- 
tions, less and less so towards the upper portion of the plant, until it at last is wanting. 
It is also readily enough seen, by focusing “through and through,” that at the lower 
portions the main stems are covered all round by a single layer of thick-walled elongate 
cells, mutually closely apposed, of various irregularly curved and crooked figure, or етеп 
somewhat rugged within—and that these cells are separated by oblique septa, these 
latter furnished with their median minute pairs of pits and stoppers, sometimes an 
extremity of some of the cells growing on so as somewhat to overlap the adjoining 
ж «Тсопев Algarum,’ no. vi. (t. 6). 
